EP3146595B1

EP3146595B1 - Electric fuse mounting

Info

Publication number: EP3146595B1
Application number: EP14824949.3A
Authority: EP
Inventors: Peter Benko; Janez TOMELJ
Original assignee: Razvojni Center Enem Novi Materiali doo
Current assignee: Razvojni Center Enem Novi Materiali doo
Priority date: 2014-05-22
Filing date: 2014-12-05
Publication date: 2018-07-04
Anticipated expiration: 2034-12-05
Also published as: PL3146595T3; WO2015178860A1; EP3146595A1; SI24733A; DK3146595T3; SI24733B

Description

The present invention concerns an electric fuse mounting, in particular for a cylindrical fuse with a melting member.
Pursuant to the International Patent Classification, such invention belongs to electricity, namely to basic electric elements, in particular for establishing of electric interconnections via a fuse with a melting member.
The aim of the invention is to create an electric fuse mounting for a cylindrical fuse with a melting member, in which the length of electric conductive elements within the casing, namely between each fuse with a melting member and each connecting terminal, would be as small as possible, and simultaneously, that despite to the absence of any supplemental accessories, any access from outside to the electric conductive components, which are in contact with the previously mentioned electric conductive elements, will be absolutely prevented.
An electric fuse mounting is disclosed in DE 10 2004 017 517 B4 and comprises a casing, which consists of an electric insulating material, and into which an electric fuse with a melting member is insertable together with other electric conductive elements. Said casing is furnished with a front surface, which is located on its front end portion and on which a cavity is available, which is intended to receive each fuse with corresponding melting member and corresponding cover, while on the opposite end portion said casing is furnished with suitable arresting means and herewith adjusted for mounting to a standardized ledge in each disposable switch hoard. Said front surface of the casing is among others due to the length of the fuse graduated, so that the central region including said cavity for receiving the fuse and each corresponding cover protrudes from the neighboring front faces, which are arranged diametrically with respect to said cavity for receiving the fuse. Two connecting terminals are available, in the area of diametrically opposite lateral surfaces of the casing, which are located adjacent to said front faces, wherein the terminal for connecting the phase conductor is located on the first lateral surface, and the terminal for connecting the neutral conductor is located on the residual lateral surface. Each of said connecting terminals is via an electric conductive contact member within the casing electrically interconnected with an electric contact, which is suitable for establishing appropriate electric contact with a fuse, when it is inserted within said cavity of the casing. A component of each of said connecting terminals is a screw, which is mounted within said casing and extends substantially parallel to the longitudinal axis of said cavity for receiving the fuse and substantially in a direction from each corresponding front face of the casing towards each corresponding connecting terminal. Consequently, upon attaching the fuse mounting onto each disposable ledge, each fuse, namely each of its belonging connecting terminals, can be electrically connected with each phase and neutral conductor, by which said conductors are attached to said connecting terminals by means of said screws. The screws must be accessible from outside in the area of the front surface of the casing of the fuse mounting, but are for security reasons located sufficiently below said front surface, so that due to their exposure to voltage during the use of the fuse, the access to screws is prevented. To this aim, a so-called finger test is foreseen, which is known to persons skilled in the art and by which it is checked, if from the outside of the casing any kind of access to said screws would be possible. Such testing is precisely defined in standards.
As mentioned, each electric contact between the fuse and said connecting terminals with corresponding contacts is established via electric conductive elements, which are usually made of copper and are pretty bulky, and therefore represent an essential portion of expenses related to manufacturing of such fuse mounting. A task of manufacturers of such fuse mounting is therefore reduction of the length of said electric conductive elements, which is in the fuse mounting according to DE 10 2004 017 517 B achieved by means of reduction of the distance between the axis of said screws to 35 mm. The diameter of the fuse however dictates a relatively large front surface of the fuse mounting, and the sole possibility of locating the passages for accessing the screws was then given in the area of the step-like transitions between the front surface and the neighboring lateral surfaces. Such approach however cannot prevent the screws from being accessed from outside, and cannot pass said finger test, so that said DE 10 2004 017 517 B proposes placement of two supplemental accessories over said passages and screws, namely two covers, which are made of electric insulating material and are embedded within appropriate guides. Applying such supplemental accessories on the one hand prevents any contact with the electric conductive components within the casing, but on the other hand manufacturing of the casing is then much more complicated and some more investments are required for the purpose of providing additional technologic equipment, which is required for manufacturing of said protecting accessories. Moreover, in practice it is always possible that such protecting accessory is damaged or is simply missing.
The present invention concerns an electric fuse mounting, wherein said mounting comprises a casing, which consists of an electric insulating material and into which an electric fuse with a melting member is insertable together with other electric conductive elements. Said casing is furnished with a front surface, which is located on its front end portion and on which a cavity is available, which is intended to receive each fuse with corresponding melting member and corresponding cover, while on the opposite end portion said casing is furnished with suitable arresting means and herewith adjusted for mounting to a standardized ledge in each disposable switch board. Said front surface of the casing is graduated, so that the central region thereof including said cavity for receiving the fuse and the corresponding cover protrudes from the neighboring front faces, which are arranged diametrically with respect to said cavity for receiving the fuse. Said cavity is defined by means of its longitudinal geometric axis, which is located in the central plane of the casing and corresponds to the longitudinal geometric axis of each fuse, while said central plane of the casing passes through said front faces. Two connecting terminals are available in the area of diametrically opposite lateral surfaces of the casing, which are located adjacent to said front faces, said terminals serving for establishing each required connection between each electric conductors and the electric fuse, wherein each of said connecting terminals is via an electric conductive contact member within the casing electrically interconnected with an electric contact, which is suitable for establishing appropriate electric contact with a fuse when inserted within the cavity of the casing. Each of said connecting terminals is furnished with a screw, which is mounted within said casing and located in said central plane of the casing and extends substantially in a direction from each corresponding front face of the casing towards each corresponding connecting terminal. Said screws of the connecting terminals are accessible through corresponding passages on the front faces of the casing of the fuse mounting, but are for the safety reasons located sufficiently below said front surface i.e. said front faces, so that the access from outside of each user by the finger is prevented.
The invention proposes that at least one of said screws is arranged in the central plane of the casing and extends inclined at a pre-determined angle relative to the central geometric axis of said cavity for receiving the fuse, so that in the direction from the front surface towards the arresting members at least one of said screws approaches to said geometric axis and simultaneously also to each residual screw.
A preferred embodiment of the invention provides that both screws are arranged in the central plane of the casing and extend inclined at a pre-detennined angle relative to the central geometric axis of said cavity for receiving the fuse, so that in the direction from the front surface towards the arresting members both screws, each per se, approach to said geometric axis and simultaneously also to each other.
In one of possible embodiments of the invention, one of said screws extends inclined relative to said axis at the angle, which amounts 2° - 10°, while the other screw extends parallel with respect to said axis. In such case it is in particular preferred, if one of said screws extends inclined relative to said axis at the angle, which amounts at least approximately 5°.
In a further possible embodiment of the invention one of said screws extends inclined relative to said axis at the angle, which amounts 2° - 10°, and the other screw extends inclined relative to said axis at the angle, which amounts 2° - 10°. A further possible aspect of the invention provides that one of said screws extends inclined relative to said axis at the angle, which amounts 2° - 10°, while the other screw extends inclined relative to said axis at the angle, which amounts at least approximately 5°. In accordance with further possible embodiments of the invention one of said screws extends inclined relative to said axis at the angle, which amounts 2° - 10°, and the other screw extends inclined relative to said axis at the angle, which amounts 2° - 10°, wherein said angles can be either equal or different. When the angles are equal, then each of said angles and should preferably amount at least approximately 5°.
The invention will be described in more detail on the basis of an embodiment, which is presented in the enclosed drawings, wherein

Fig.1: is a perspective view of an electric fuse mounting with removed fuse;
Fig.2: is a front view of the electric fuse mounting with removed fuse;
Fig.3: is a top view of the electric fuse mounting with removed fuse;
Fig.4: is a partial cross-section in perspective view of the electric fuse mounting with removed fuse in accordance with Figs. 1 - 3;
Fig.5: is a cross-section of an electric fuse mounting with removed fuse aling the plane A - A according to Fig. 1; and
Fig.4: is analogously like Fig. 4 a partial cross-section in perspective view of the electric fuse mounting with removed fuse in accordance with Figs. 1 - 3, however in its mounted state.

An electric fuse mounting according to the invention comprises a casing 1, which consists of an electric insulating material and into which a not shown cylindrical electric fuse with a melting member is mounted together with other electric conductive components. Said casing 1 is furnished on its front side with a front surface 11, on which a cavity 12 is foreseen, which is adjusted to receive a fuse and suitable cover, which is also not shown in the drawing, while on the opposite end portion said casing 1 is furnished with suitable arresting members 13', 13" and herewith adjusted for attaching on a standardized ledge 8 on each particular switch panel (Fig. 6). Said front surface 11 of the casing 1 is graduated, among others due to the length of the electric fuse, and its central region 11' together with said cavity 12 for inserting the fuse protrudes from neighboring front faces 11", 11''', which are arranged diametrically with respect to said cavity 12 for inserting the fuse.
Said cavity is defined by longitudinal geometric axis 120, which corresponds to the longitudinal geometric axis of each cylindrical fuse.
Connecting terminals 15', 15" are available in the area of lateral surfaces 14', 14" of the casing , which are also located diametrically opposite and adjacent to said front faces 11", 11''', wherein the first connecting terminal 15' is intended for connecting of the first electric conductor (not shown) and arranged on the first lateral surface 14', while the residual connecting terminal 15" is intended for connecting of the second electric conductor (not shown) and arranged on the residual lateral surface 14" of the casing 1.
Each of said connecting terminals 15', 15" is within said casing 1 via appropriate electric conductive contact member 16', 16" electrically interconnected with a contact 160', 160", which is adjusted for establishing of appropriate electric contact with the fuse, when inserted within said cavity 12 in the casing 1.
Like in Figs. 1 - 6, each contact 160', 160" can represent an integral part of said electrically conductive connecting member 16', 16' i.e. can be made integrally therewith.
A component of each of said connecting terminal 15', 15" is a screw 17', 17", which is mounted within the casing 1 and extends substantially in a direction from each corresponding front surface 11', 11" towards each corresponding connecting terminal 15', 15", Moreover, each of said screws 17', 17" is substantially aligned with each corresponding connecting terminal 15', 15". Consequently, as soon as the fuse mounting is attached onto each corresponding ledge 8, the fuse, namely each connecting terminal 15', 15", can be then electrically interconnected with each corresponding electric conductors, wherein said electric conductors are attached to said connecting terminals 15', 15" by means of said screws 17', 17". Said screws 17', 17" are inserted through corresponding passages 18', 18" located on the front surfaces 11', 11" of the casing 1 and must be accessible to each user from the front side of the casing 1, but are also due to security reasons arranged sufficiently below the front surface 11 and said front faces 11", 11''' in order to prevent any undesired access, since during the use of the fuse they are exposed to voltage. The distance between said screws 17', 17" and said front faces 11", 11''' is regularly such that the fuse passes the so-called finger test, which is standardized and well known to any person skilled in the art, and by which a checking is performed, if by any kind of contact can be established means of a finger with said screws 17', 17" from the front side of the casing 1, when the fuse is inserted.
When bearing in mind that the passages 18' 18", which allow the access to the screws 17', 17", are located on said front faces 11", 11''' on opposite sides of the cavity 12 and do not extend to the protruding central region 11', upon installation of the electric fuse mounting into each switch board 9 (Fig. 6), said passages 18'. 18" can be covered with decorative plates 9' 9", which like the switch board as such consist of an electric insulating material.
When bearing in mind the previously described concept of the known electric fuse mounting, the invention proposes contrary, namely that the screws 17', 17" are not directed parallel to said central geometric axis 120 of the cavity 12 intended for receiving of the fuse, since at least one of the screws 17', 17" is inclined at a pre-determined angle α, β with respect to said axis 120 in such manner that in the direction from the front surface 11 of the casing 1 towards the arresting members 13', 13" on the opposite end portion of the casing 1 at least one of said screws 17', 17" converges to sais axis 120.
Generally speaking, it is preferred if both screws 17'. 17" are inclined at a pre-determined angle α, β relative to said axis 120, so that said screws 17', 17", when observed from the front surface 11' towards the arresting members 13', 13", converge to the axis 120 and simultaneously also to each other.
In the shown embodiment (Fig. 5), one of screws 11', 17", in the particular case the first screw 17'. is inclined relative to said axis 120 at the angle α, while the residual screw 17" is inclined relative to said axis 120 at the angle β.
In general, the angles α and β may be either equal or different, and one of them may even be 0°.
The invention generally provides that each of said angles α and β is selected within the range of 2° - 10°, and is preferably at least approximately 5°,
Thanks to the previously described arrangement of said screws 17', 17", at least one of bulky copper contact members 16', 16" can be simply shortened, which in particular in the mass production leads to essential savings without the need on providing any supplemental protecting requisite in order to prevent the access to the screws 17', 17" from the side of the front surface 11 of the casing 1.

Claims

Electric fuse mounting, comprising a casing (1) consisting of an electric insulating material, into which an electric fuse with a melting member is insertable together with other electric conductive elements, wherein said casing (1) is furnished with a front surface (11), which is located on its front end portion and on which a cavity (12) is available, which is intended to receive each fuse with corresponding melting member and corresponding cover, while on the opposite end portion said casing (1) is furnished with suitable arresting means (13', 13") and herewith adjusted for mounting to a standardized ledge (8) in each disposable switch board (9), and wherein said front surface (11) of the casing (1) is graduated, so that the central region (11') including said cavity (12) for receiving the fuse and each corresponding cover protrudes from the neighboring front faces (11", 11'''), which are arranged diametrically with respect to said cavity (12) for receiving the fuse, and wherein said cavity (12) is defined by means of its longitudinal geometric axis (120), which is located in the central plane (100) of the casing (1) and corresponds to the longitudinal geometric axis of each fuse, while the central plane (100) of the casing (1) passes through said front faces (11", 11'''), and wherein in the area of diametrically opposite lateral surfaces (14', 14") of the casing (1), which are located adjacent to said front faces (11", 11'''), two connecting terminals (15', 15") are available, which serve for establishing of each required connection between each electric conductors and the electric fuse, wherein each of said connecting terminals (15', 15") is via an electric conductive contact member (16" 16") within the casing (1) electrically interconnected with an electric contact (160', 160") suitable for establishing appropriate electric contact with a fuse when inserted within the cavity (12) of the casing (1), and wherein each of said connecting terminals (15', 15") is furnished with a screw (17', 17"), which is mounted within said casing (1) and located in said central plane (100) of the casing (1) and extends substantially in a direction from each corresponding front face (11", 11''') of the casing (1) towards each corresponding connecting terminal (15" 15"), and wherein said screws (17', 17") of the connecting terminals (15', 15") are accessible through corresponding passages (18', 18") on the front faces (11", 11''') of the casing (1) of the fuse mounting, but are for the safety reasons located sufficiently below said front surface (1) i.e. said front faces (11", 11'''), so that the access from outside of each user by the finger is prevented, characterized in that at least one of said screws (17', 17") is arranged in the central plane (100) of the casing (1) and extends inclined at a pre-determined angle (α, β) relative to the central geometric axis (120) of said cavity (12) for receiving the fuse, so that in the direction from the front surface (11) towards the arresting members (13', 13") at least one of said screws (17', 17") approaches to said geometric axis (120) and simultaneously also to each residual screw (17', 17").
Electric fuse mounting according to Claim 1, characterized in that both screws (17', 17") are arranged in the central plane (100) of the casing (1) and extend inclined at a pre-determined angle (α, β) relative to the central geometric axis (120) of said cavity (12) for receiving the fuse, so that in the direction from the front surface (11) towards the arresting members (13', 13'') both screws (17', 17") each per se approach to said geometric axis (120) and simultaneously also to each other.
Electric fuse mounting according to Claim 1, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α, β), which amounts 2° - 10°, while the other screw (17', 17") extends parallel with respect to said axis (120).
Electric fuse mounting according to Claim 3, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α, β), which amounts at least approximately 5°.
Electric fuse mounting according to Claim 2, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α), which amounts 2° - 10°, and the other screw (17', 17") extends inclined relative to said axis (120) at the angle (β), which amounts 2° - 10°.
Electric fuse mounting according to Claim 5, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α), which amounts 2° - 10°, and the other screw (17', 17") extends inclined relative to said axis (120) at the angle (β), which amounts at least approximately 5°,
Electric fuse mounting according to Claim 5, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α), which amounts 2° - 10°, and the other screw (17', 17") extends inclined relative to said axis (120) at the angle (β), which amounts 2° - 10°, wherein the angles (α) and (β) are different.
Electric fuse mounting according to Claim 5, characterized in that one of said screws (17', 17") extends inclined relative to said axis (120) at the angle (α), which amounts 2° - 10°, and the other screw (17', 17") extends inclined relative to said axis (120) at the angle (β), which amounts 2° - 10°, wherein the angles (α) and (β) are equal.
Electric fuse mounting according to Claim 8, characterized in that each of said angles (α) and (β) amounts at least approximately 5°.